Apparatus for fine crushing



April 1960 J. A. KYRIAZI 2,931,582

APPARATUS FOR FINE CRUSHING Filed Dec. 17, 1957 U'nited SEES- Patt fiAPPARATUS FOR FINE CRUSHING Jean A. Kyriazi, Alexandria, EgyptApplication December 17, 1957, Serial No. 793.423 Claims priority,application Belgium August 4, 1956 6 Claims. (Cl. 241-56) This inventionrelates to an apparatus for grinding and sizing of solid materials ofthe type in which the materials in a stream of air are hurled by arotating member against a stationary member consisting of a peripheralannulus of longitudinal tubular pockets where the particles are reducedboth by reciprocal grinding and by impact. The efficiency of this typeof apparatus is determined by the quantity of air going to the pocketsand by the length of time these particles stay in the pockets. These twoefiiciency conditions oppose each other and the air'introduced into thepockets tends to escape immediately carrying away the particles ofmaterials without leaving them time for sizing other than through directimpact against the walls of the pockets. A large amount of air isnecessary to accelerate, to move and to size the particles. The firstobject of the instant invention is to enable the introduction of largequantities of. air into the tubular pockets and at the same time to:retain the particles which are insufficiently ground in th pockets.

In this type of apparatus the amount of air necessary is produced byfans. The particles are accelerated both by air and by the blades offans and the separation is brought about by the resulting directiongiven to a particle as it crosses a radial fan from the periphery to thecenter. The present invention is characterized by the provision of a gapbetween each of the tubular pockets so that a portion of the air flunginto the tubular pockets- 7 by centrifugal action may pass through thegaps and join a suction air flow surrounding the annulus of tubularpockets, which are accordingly installed at a distance from the insidewalls of the grinding chamber of the stator so that an air spacesurrounds the peripheral annulus of the. tubular pockets. The firstobject of the instant invention is realized by the above doublecharacteristics. Another object of the instant invention is to preventthe particles from concentrating in the; bottom of the apparatus andclogging up the bottom pockets of said apparatus. A bottom opening inthe stator serves to permit removal from the circuit of the particleswhich have lost their velocity.

Still another object is to adapt to the apparatus a sizing system toreturn the insufliciently ground particles to the grinding zone.

The practical embodiment of this invention is described, by way ofexample, in the following specification and in the attached figure inwhich:

Figure 1 is a longitudinal section of an apparatus according to theinvention; and

Figure 2 is a section on line 2--2 through the peripheral annulus oftubes in the apparatus of Figure 1.

The apparatus described in these figures consists of a rotor shaft 1running through a grinding chamber 14 and a suction chamber 12. Thegrinding chamber comprises a stator 2, a lateral wall 23 having an airinlet therein, a loading hopper 3 mounted on the wall 23 over opening23' therein, and a peripheral ring of openended tubular pockets. formingwith the wall an air casing. The pockets 10 are each separated by asmall a peripheral angle iron 13 welded to the pockets at"27.'

An opening 9 is provided at the bottom of the grinding chamber. Therotor is a projecting fanand comprises a projection disc 4 on one sidefitted at'its periphery with blades 7 joined by an annulus 6; On theother side of the disc are mounted blades 15. On the 'shaft'l betweenthe disc 4 and the wall 24 of stator 2 separating the chambers 12 and14- a separating fan 17' having vanes is fixed. The lateral flange 21ofa connecting t'u'be'18 connected to fan 17, and the separating wall24 issealed to the tube 18 by means of packing 16. The connect ing tube 18 isconnected with a centrifugal exhaust device 19 mounted on the shaft 1 inthe suction chamber 12. A discharge nozzle 20 is mounted on chamber 12.An air duct 8 open at its lower end is mounted on wall 23 and leads fromopening 9 to air inlet 5.

In operation, a first double air current isp'rodu'ced.

one along the inside wall of the stator, and the other through the fanformed by a disc 4 and blades 7; 'From apoint radially inwardly of thetubular pockets the compressed air of the second current escapes throughthe gaps between the tubes and joins the peripheral air current alongthe stator wall, and the remaining air mixes with the'first current atthe outlet of the pockets. The air current passes through the vanes ofthe separating fan 17 and is ejected through the escape nozzle 20 ofsuction chamber.

'The material introduced into the loading .hopper' 3- flows into theprojecting fan through opening 23' and is violently projected by theblades 7. The particles whirl around the pockets 10, where by reciprocalwear and impact they are ground. The fines are carried away with thecompressed air current passing through,

the gaps between the pockets. The particles remaining in the tubes10.are projected at the open end of-' the tubes at high speed into theseparating wall 24-which has a deflecting surface 24' where a firstseparation takesplace. face and are directed against. the projectiondisc 4 which throws them against the rounded wall of the grindingchamber to the center of the annulus 6'and they are taken up again inthe grinding circuit. particles which have lost speed fall into thebottom of the apparatus where they are'removed by gravitythrough thedischarge opening 9. The duct 8 servesto bring back into the circuit theair 1 loaded with fine' particles escaping through the discharge opening9m- The finely ground material coming out of the tubular pockets will,on the other hand, be sucked through the separating fan 17 through thecircular opening serving as the communication between the grinding andsuction chambers. The blades of this fan strike the particles in thestream of air being drawn through it, and the resultant force acting onthe particles is the combined force imparted to them by the air streamand by the blades of the fan. Thus the larger particles will be knockedout of the stream of air flowing through the fan and the smallerparticles will remain in the stream and be carried through the fan. Thelarger particles will fall back into the grinding chamber 14 to becollected as described above. A portion of air escapes radially from thepockets 10 through the gaps separating the pockets, carrying alongparticles small enough not to be retained in the pockets by the cyclonicaction of the inside walls of the pockets. The peripheral portion of thegrinding chamber 14 being in communion iiatentedt App 1 5 The coarseparticles follow the defiectingHsur- Thetion with the suction system,this radial 'escapement is encouraged by the intensive whirling movemententer 'ing the pockets slightly. This installation enables theintroduction of. large quantities. of air and at the same.

in the bottomaof the grinding chamber and eliminate them either throughthe opened orifice in' the bottom of; the apparatus, in the case whereit is desired to remove thegi it contained in the material to be groundand which concentratesin the particles gathered in the bottom of thedevice, o r by making those particles return to the center oi theprojccting fan with the aid of an appropriate device.

-The third object of the instant invention is accompiished by thedeflecting surface which first performs a sizing and then a direction ofthe particles sized against the fan by which they are returned to thecenter of the projecting fan.

The constructional details of this invention may vary. The pockets maybe replaced partially or completely by a fiat, or grooved, or corrugatedsurface. of pockets and bladescan be adjusted so as to obtain ultrasonicvibrations with an easier subsequent recovery re the materiah Thesuction system may be replaced by another. systern forminga part of orindependent from the apparatus. The turbo-suction device can be designedto op-' erate simultaneously as a centrifugal collecting device with 'abottom airtight discharge. The apparatus may consist of two pulverizingchambers placed at both sides ofa central suction chamber.

The separation device may be limited to the deflectors only. The fan forseparation can be replaced by a screen. only, the air transporting thetines through the gaps and the coarse particles being recirculated.

For grinding low melting point material a double shell may-surround theannulus of pockets and be filled with cooling medium.

The apparatus according to this invention may be used as a grinderpermitting the grinding of a wide range of material, as a grinder andsizing unit, as a grinder and degritting apparatus, as a burner andgrinder for solid.

fuels, as a grinder-mixer or mixer unit, as a grindersizing andrecuperation unit, etc.

By: eliminating the material ejected to the base of the not cause anyclogging, while at the same time they can The separation may be e ectedby the pockets:

bottom airtight discharge it is possible to eliect separations by degreeof grindability or by the dilterentiation of the shapes, by alternatingor sharpening sizing devices.

I claim:

1. An apparatus for grinding material comprising a grinding chamberhaving an air and a material inlet thereto, a rotor rotatably mountedtherein, a fixed annulus mounted coaxially around said rotor and spacedradially therefrom, said annulus being spaced radially in- I Because ofthe air chamber surrounding the ring of pocket s,it is easy torecuperate the particles losing speed The number between said grindingchamber and said air evacuation system.

3. An apparatus for grinding material comprising a grinding chamber, asuction chamber adjacent said grinding' chamber]. a separating wallbetween said chambers,

a shaft rotatably mounted through said chambers, a projecting fanmounted on said shaft in said grinding chamher and having a projectingdisc forming a part thereof, said grinding chamber having an air inletcoaxial with said shaft on one side of said projecting disc, a hopper onsaid grinding chamber, an annulus mounted in said grinding chamberspaced from the walls of said chamber and surrounding said projectingfan and spaced therefrom and having a plurality of open-ended tubularpockets therein, said pockets opening toward said projecting turbineand'being spaced from each other, said grinding chamber further havingan evacuation outlet coaxial with said shaft in said separating wall,separating means on said shaft in said grinding chamber on the oppositeside of said projecting disc from said air inlet,

a tube connecting said separating means and extending through saidevacuation outlet and rotatably sealed with said separating wall, and asuction fan mounted on said separating means comprises a separating fan.

-5. An apparatus as claimed in claim 3 in which said:

separating wall has at least one circular deflector thereon.

machine, or by efiecting a separating action by the sep-.

aratiug fan-or by installing separators in series with a 6 An apparatusas claimed in claim 3 in which a part of said annulus consists of aplane surface.

References Cited in the file of this patent UNITED STATES PATENTS

